Magnetic Tapes

Sub-Zero Cold Storage for the Permanent Preservation of Photographs,
Motion Picture Films, Books, Newspapers, Manuscripts, and Historical Artifacts

Remember, this transfer that you (or I) are about to undertake may be the last time (and hopefully the best time) that the original is transferred. Here are some suggestions:

1. Make at least two masters and a listening copy. Keep one set of masters off-site. //

2. Make straight transfers before processing. Save these as better noise processing algorithms may be available in the future.

3. Save a good portion of the noise footprint on the tape without other signal information for later noise reduction processing.

4. At first, worry less about a final product than getting a good, clean transfer with as few artifacts as possible.

5. Above all, listen…are you getting the best transfer you think you can?

This checklist is not a complete guideline. It contains only those items that experience and testing show will have an immediate or severe effect on magnetic tape. Failure to adhere to the items on this list may cause premature loss or deterioration of magnetic tapes and should be considered misuse of the medium. These are minimum handling requirements that summarize good practices.

If the restoration/preservation reformatting is for an institutional client, then the first transfers should be as unprocessed as possible — at least the initial copies that are archived should be done that way. The main reason for this is that processing algorithms will always get better and they may hide some information that is useful to future researchers–information that today we consider “noise.”

I am conservative when setting audio levels when making transfers because there is no way of knowing the loudest portion of the signal in advance. So I generally transfer at 24 bits and then raise or normalize the level prior to dithering down to 16 bits for the distribution copy. If I’m working on music, I will generally archive the 88,200 ks/s or 96,000 ks/s files before the normalization.

Processing should generally be done on a copy. The exception to this in my mind are private clients who want the best possible copy of their parents’ wedding, or some other important event. If applied conservatively, noise reduction and equalization will be appreciated by these clients and most of them won’t care a bit that it’s been processed. I keep the unprocessed files on my servers until I am sure the client is happy with the processed version.

As to what to use, there are a wide variety of options available. At the high-end, this falls into the category of “remastering” rather than simple restoration and I’m sure there are options that I’m not aware of.

As a first step, I am very pleased with the basic capabilities built into Samplitude. In addition to that, I use Algorithmix Noise Free Pro as well as the Sound Laundry suite. Really tough projects can often be improved by the filters in Diamond Cut 6 Live/Forensics and most of the filters are available in the lower-priced Diamond Cut 6. Diamond Cut and their main dealer, Tracertek, often run sales which was how I upgraded to Live/Forensics.

Other products with excellent reputations are Cedar Cambridge, Quadriga Audio Cube, and many others. Listening to and discussing with other users via one or more of the mailing lists listed here is very useful.

Often a tape comes in for restoration that has been poorly wound or poorly stored. Here is an example:

cinched tape

One of the interesting things about this particular tape was it had been recently wound on a constant-tension professional machine prior to shipping to me.

We think that the entire tape had not been re-wound, allowing the higher tension wind to compress the inner core slightly, causing this cinching. After transferring the tape (which didn’t show much ill effect for its cinching), we still found it difficult to get the tape to wind smoothly on the reel.

Therefore, our current suggestion is if you find a tape like this, do not rewind it and attempt to clear up the cinching unless you are also ready to transfer the tape, as there are no guarantees that it can be wound better after unwinding.

The Permanence and Care of Color Photographs: Traditional and Digital Color Prints, Color Negatives, Slides, and Motion Pictures

by Henry Wilhelm
with
contributing author Carol Brower

In 2006, I wrote a blog post (here) called “Let Sleeping Tapes Lie: What to do with poorly wound tapes”. For years, tape experts have been suggesting that it is not as good an idea to rewind tapes as was originally thought. This was partially based on the fact that most rewinding in archives was done on the oldest, junkiest machines so as to not wear out the good machines. Unless rewinding is done on high-quality tape transports, it is indeed counter-productive.

ere are a list of my picks of free and low-cost software tools. I am sticking with Samplitude Professional for audio and Adobe Photoshop and Adobe Photoshop Lightroom for photo-graphics. The other alternatives, however, are wide open.

The International Association of Sound and Audiovisual Archives (IASA) has released their landmark Guidelines on the Production and Preservation of Digital Audio Objects as a free web (HTML) edition, available here. http://www.iasa-web.org/tc04/audio-preservation

At some point, this tape was played on a 1/4-track machine that injected hum onto the left channel. Here’s what the magnetic viewer showed:

At the very top we can see a remnant of the left channel material, then the 120-Hz bars (62.5 mil spacing), then the remainder of the left channel material. In the middle is the guard band and at the bottom, the right channel.

July 20, 2018
Website Notice

Note: This website (moonviews.com) has not been regularly updated since 2014. Now that the project’s data has been submitted to NASA, this website will no longer be updated but will be maintained as an online archive of the LOIRP’s prior activities. Thank you for your interest in – and support of – our project. //

The Lunar Orbiter Image Recovery Project (LOIRP) is a project to digitize the original analog data tapes from the five Lunar Orbiter spacecraft that were sent to the Moon in 1966 and 1967; it is funded by NASA, SkyCorp, SpaceRef Interactive, and private individuals.[1]

The first image to be successfully recovered by the project was released in November 2008. It was the first photograph of the Earth from the Moon, taken in August 1966. On February 20, 2014, the project announced it had completed the primary tape capture portion of the project.[2] One medium resolution image, most of one high resolution image and parts of three others are missing, apparently due to lapses at the time they were being recorded.[3] The rest of the Lunar Orbiter images have been successfully recovered[2] and have been published in NASA's Planetary Data System.

“I’ve spent the past week in Mountain View, California, hanging out with a group of Lunar Orbiter Image Recovery Project (LOIRP) hackers who are working out of an abandoned McDonald’s on the NASA Ames base. For more than five years, LOIRP technologists (or techno-archeologists, as they prefer to be called) have been reverse-engineering analog tape drives and developing new software in an attempt to unearth some of the first images of the moon that were taken by unmanned lunar orbiters in advance of the manned Apollo missions of the late 1960s. Upon entering the building (affectionately called “McMoon’s” by those who work within it) for the first time, I was greeted by familiar architecture. The drive-thru windows, menu light boxes, stainless steel counters, fiber glass tables and the ghosts of corporate brand ephemera all remain. However now they coexist under a jolly roger with a literal mountain of vintage 2-inch tape reels that contain trapped data, refrigerator-sized Ampex tape drives, an army of Mac workstations and a seemingly endless supply of analog tape decks, monitors, cables and soldering supplies.”

“Our memory is dissipating. Hard drives only last five years, a webpage is forever changing and there’s no machine left that reads 15-year old floppy disks. Digital data is vulnerable. Yet entire libraries are shredded and lost to budget cuts, because we assume everything can be found online. But is that really true? For the first time in history, we have the technological means to save our entire past, yet it seems to be going up in smoke. Will we suffer from collective amnesia?”
The Lunar Orbiter Image Recovery Project is featured starting at 17:15. This segment was filmed in early 2014.

Vigilant migration of data as new storage techniques become available is the only way to assure long-term preservation. Even if the IRIG tapes are found, we are almost at the point where the tapes would be un-decipherable. I think one of my machines could play them (I say think as I’ve never tested it to full 500 kHz bandwidth), but I don’t have the specialized video decoder. NASA apparently preserved some equipment should the tapes ever show up.

This also raises another spectre. We MUST be selective as to what we keep in our archives because if we keep everything we won’t be able to afford it–or find it. This is one of the key jobs that archivists do. However, blindly following retention practices, as was done by NASA for the IRIG Apollo 11 tapes, needs to be tempered by historians as well. Certain small subsets of data (moonwalk slow scan video) are much more important than others (astronauts’ blood pressure and other biometrics throughout the entire flight).

All organizations who keep archives need to address this. In a generation (or less) if we save everything, it will become an overwhelming burden and the high points will be lost if they are not properly indexed.

(free) 333-page technical document on sound restoration titled "Manual of Analog Sound Restoration Techniques." It's written by Peter Copeland of The National Sound Archive in England (part of the British Library Board), and it's a remarkable and interesting document.

I don't agree with everything Copeland says, but he makes a number of good points in his report, and there's a lot of very good information in it, particularly on vinyl restoration techniques. Apparently Copeland died in 2006 without finishing the manuscript; parts of it are in desperate need of editing, and the info is dated in sports, but there's still a treasure-trove of good information there. Note that Copeland's approach is very scientific and engineering-based; subjective audiophiles may take issue with some of his opinions.

It's available as a free PDF at this link:

http://www.bl.uk/collections/sound-archive/pdf/analoguesoundrestoration.pdf

Copeland reportedly put about ten years of research into writing the document, and it's very well-done. Anybody who's trying to do restoration and mastering of vinyl, 78RPM discs, and analog tape should read it.

https://web.archive.org/web/20080920161543/http://www.bl.uk/collections/sound-archive/pdf/analoguesoundrestoration.pdf

The late Peter Copeland wrote a handbook concerning analogue sound restoration. It is required reading. When Peter died in 2006, I despaired that this would ever see the light of day. In 2008-09, the British Library released it as a free PDF file available here.

The IASA “Green Book” TC-04 Guidelines on the Production and Preservation of Digital Audio Objects can be purchased from IASA. The Second Edition is available online.

The CoOL (Conservation On Line) site has many resources. In particular, read Gilles St-Laurent’s 1996 article on The Care and Handling of Recorded Sound Materials.

The National Recording Preservation Board of the Library of Congress and the Council on Library and Information Resources March 2006 Capturing Analog Sound for Digital Preservation: Report of a Roundtable Discussion of Best Practices for Transferring Analog Discs and Tapes

This Tape Timing Chart is approximate. Most reels will contain a bit more tape than indicated time implies, typically about 6%. The footage is actual.

These timings are for one program. There can be as many as four mono programs on one 1/4-inch tape.

The bottom-line is that destroying the originals after digitizing them should not be taken lightly. Really think about the implications. Put yourself 10 - 20 years in the future and think about what the implications of your decision might be. Is destroying the originals a decision that you will regret (or that your successors will regret)?